Adam Handling is a man on a mission. What that mission is, however, is up for debate. Does he want to redefine the rules of fine dining in London? Does he want to teach the restaurant scene truly sustainable business practices? Does he want to build a business empire that encompasses restaurants, cafés, cocktail bars and hotels? A couple of hours in his company is enough to ascertain that the answer is probably 'all this and more'.

A proud Scotsman, Handling came into restaurants by way of an apprenticeship in the Gleneagles kitchen when he was 15, which he describes as "a very, very hard kitchen, but incredible." Stints in kitchens in London, Newcastle and Fife followed, before Handling opened his first restaurant with his name above the door – Adam Handling at Caxton, in St Ermin's Hotel – and even did a stint on BBC's Great British Menu. Both gave him a platform to showcase his creative, stylish cooking, but he longed for a business he could own. "I was tired of being taken for a mug, working for someone who wasn't particularly nice to work for," he says. "So me and the team said 'to hell with it – now it's time to do it for ourselves'. And we did. And it was the best decision I ever made."

Since then, Handling hasn't looked back. He pioneered a style of cooking that skirts between fine dining (tasting menus and conceptual dishes) and casual (street art and pumping music) at The Frog E1 in the Old Truman Brewery. Handling quietly opened a zero-waste café, Bean & Wheat, to complement the restaurant by making use of its food waste, before opening the flagship Frog by Adam Handling in Covent Garden and the accompanying Eve Bar.

Now, with the lease up on 'E1', he's moving it up the road. Frog Hoxton is three venues (the restaurant, bar Iron Stag and another Bean & Wheat, which he says he'll open one of for every restaurant) that blend together exciting casual drinking and dining with a philosophy rooted in sustainable cooking. His five dishes, and his reflections on them, sum up the endeavours of a truly restless mind.

When I opened my first restaurant, we had 50 journalists, food critics and influential people coming in to taste my menu for the very first time. And my mother told me she was going to be vegetarian. So I created this dish, and I called it 'Mother' to try to embarrass her. It's salt-baked celeriac, and then on the plate you've got truffled cheese, a confit yolk, and it's covered in limes and dates. It's a dish that covers your whole mouth – salt, sweet, sour, bitter and umami. Back then I used really top-end ingredients – probably because I wasn't confident, and you feel like cooking lobster, beef fillet and foie gras is the way to cook. And because I had zero self-esteem, I covered it in black truffle. It seemed to do the best out of all of the dishes on the menu for this one particular dinner, and I've kept it on ever since.

This is one of the first signature dishes that I created at E1, and it had mixed reviews: we had some people loving it and some publications saying it looked like a tampon. We burn the caramel and reform it into a tube. Inside that is a beetroot and yuzu gel, pickled beetroot, and then a beetroot panna cotta, and it's all covered in beetroot powder. We are British, at the end of the day, and beetroot is one thing that we grow in abundance, so it's about giving it a pedestal to stand on. It's a dish that makes the transition between a main course and dessert. And when you eat it, it's sweet and sour and then it's earthy. I think that transition, instead of a sorbet or something more traditional for a pre-dessert, is great. I won't take it off Frog Hoxton's menus.

With this, I wanted to take the flavours of tiramisu, but have traditional chocolate mousse glazed up deliciously, a beautiful chocolate shortbread, and make it really elegant – a lovely little dish. You've got that nitrogen-frozen tiramisu mousse – it's very fresh, not overpowering with alcohol or coffee, and it works magically with the chocolate – and then I cover the whole thing in mushroom powder. I feel that the mushrooms and the coffee and chocolate work incredibly well. I don't tell diners that when I serve the dish, it's just there. Then you put this frozen tiramisu on the top of it. It's one where I wanted to dig my heels in and say that it doesn't need to look beautiful to make it taste good. I wanted the diner to smash the life out of it at the table and then eat it.

This was a dish we put on in Covent Garden, and E1, but Covent Garden was where I developed it to the stage it's at now. It's all about using phenomenal ingredients. If we're going to do pork, presa Ibérica is an amazing cut to do it with, and it's utilising a cut of meat that doesn't really get used that often. This is where the cauliflower idea came from: the florets were roasted; the stalks were barbecued, burnt and then made into a puree; and then the kimchi is made using the leaves of the cauliflower. So that one humble little cauliflower is covered in lots of ways in this dish. We used everything from that one single vegetable – that's how that dish got created.

Hake and tomatoes is about two things: it's Covent Garden, and it's also my future. The sauce itself and the fish itself will never change – the garnish does, it changes with the seasons, and at the moment tomatoes are amazing – but that sauce, the sweet and sour crab sauce, is incredible. It's finished with ginger, lemongrass, basil and coriander, so it's very, very fresh and a little bit spicy. That sauce is what got Covent Garden recognised, but the way it's presented in the white bowl so elegantly like that is actually the future: I'm opening a hotel at the end of this year, and obviously even though it's six months away, there's a lot of work to do. This dish is one I'll serve at the hotel – that's why when I think of it, I think of the future as well.

Find out more at adamhandling.co.uk